#include<stdio.h>
main()
{
    int a = 21,i;
    printf("Game begin:\n");
    while(a>0)
    {
        do{
            printf(" How many sticks do you wish to take (1~%d) ?", a>4 ? 4:a);
            scanf("%d",&i);
        }while(i>4 || i<1 || i>a);
        if(a-i>0) printf(" %d sticks left in the pile.\n",a-i);
        if((a-i)<=0){
            printf(" You have taken the last sticks.\n");
            printf(" * * * You lose! \nGame Over.\n");
            break;
        }
        else
        printf(" Computer take %d sticks.\n",5-i);
        a-=5;
        printf(" %d sticks left in the pile. \n",a);
    }
}